1. Field of the Invention
The invention relates to a positioning system and, more particularly, to a positioning system which utilizes antenna-assisted positioning method to achieve two-point positioning.
2. Description of the Prior Art
In general, three-point positioning method is mostly applied to wireless communication, such as time of arrival (TOA) algorithm, receive signal strength (RSS) algorithm and other similar positioning techniques, as shown in FIG. 1A. However, no matter what is applied to, three base stations are required for positioning a mobile device. In other words, if TOA algorithm or RSS algorithm is applied to a two-point positioning method, it will be difficult to make a precise judgment on the position of the mobile device, as shown in FIG. 1B.
When applying two-point positioning method to the mobile device, angle of arrival (AOA) is mostly used, as shown in FIG. 2. AOA algorithm measures at least two different angles α1 and α2 of arriving signal at the base station 1 and 2 transmitted from the mobile device 3 to determine a position of the transmitting signal. In order to confirm direction of the signal, an intelligent antenna array system has to be disposed on an antenna of a base station. As a result, huge cost is induced. Besides, AOA algorithm is also easily affected by environment factors, such as none-line-of-sigh (NLOS).
Accordingly, the scope of the invention is to provide a positioning system, so as to solve the aforesaid problems.